Any ideas?

[AGA-man]

On my last bike I used Castrol GTD 10/40 with good results, now I've just got a Honda NTV 650 V twin water cooled almost the same as a Hawk / Bros, the gear shift was good untill I changed whatever oil was in there for the Castrol now its crap notchy and most of the time getting neutral on the way to second. Should I stick with 10/40 and go to another brand or go for 20/40

 

[Blake Sobiloff]

10W-40 and 20W-40 oils, assuming the same base oil and additive package, will perform the same. What viscosity is recommended in the owner's manual?

 

[AGA-man]

The book recommends 10/40.

 

[KW]

That bike just might not like the Castrol 10W40. Try another brand and see if it likes it any better. Sometimes it take a bit of trial and error to find one that a particular bike likes. A diesel rated oil may be the answer.

 

[sunruh]

GTX doesn't seem to last long in bikes. their motorcycle spec oil isn't much better either. what ambient temp ranges do you expect to be riding in AGA?

 

[jkhawaii]

Give redline oil a try, use it in my buell and my brothers 750 gsx-r

 

[KBFXDLI]

Try ANY synthetic if you have a water cooled bike. I have had the neutral issue until I went synthetic. I'd try the 15w40 or 20w40 syn.

 

[AGA-man]

Castrol GTD is a diesel oil,I usally only ride in warm weather, I'd love to try Redline or Rotella but if they are in the UK they ain't easy to find so I'll try a Synth oil and see how that goes. Thanks for the replies.

 

[sunruh]

i wondered if GTD was a typo of gtx or not since you are in the UK.
can you give us a url that shows the specs on this oil please?
if it is a HDEO, i would tend to think it would be pretty decent in your bike.

 

[pajim17057]

I just put redline 10w40 in my vulcan 800. It shifts like butter.

 

[KBFXDLI]

Redline oils are superior but are $7 a quart. I'd try the Rotella first and see how it runs at $7 a gallon.